Brain and liver targeted overexpression of O6-methylguanine DNA methyltransferase in transgenic mice.
Brain and liver targeted overexpression of O6-methylguanine DNA methyltransferase in transgenic mice.
复制标题
转基因小鼠脑和肝脏靶向过度表达 O6-甲基鸟嘌呤 DNA 甲基转移酶。
DOI：
10.1093/carcin/14.8.1537
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发表时间：
1993
期刊：
影响因子：
4.7
通讯作者：
Adrian,GS
中科院分区：
文献类型：
--
作者：
Walter,CA;Lu,J;Bhakta,M;Mitra,S;Dunn,W;Herbert,DC;Weaker,FJ;Hoog,T;Garza,P;Adrian,GS
O 6甲基鸟嘌呤DNA甲基转移酶（MGMT; EC 2.1.1.63）是一种不寻常的DNA修复蛋白，它直接特异性地修复诱变前的DNA损伤，而不涉及其他蛋白。MGMT通过接受半胱氨酸残基上的烷基，以独特的化学计量反应从DNA中的O 6-烷基鸟嘌呤上除去烷基。MGMT的细胞内水平在不同组织之间变化，并且似乎与单功能烷化剂诱导的组织特异性肿瘤发生呈负相关。由于MGMT单独起作用，因此对其表达的遗传操作可能为其对细胞对烷基化毒性和肿瘤诱导的抗性的贡献提供有价值的见解。人MGMT全长cDNA与人转铁蛋白（TF）5 '侧翼区（TF/MGMT）的一部分融合。产生携带TF/MGMT转基因的转基因创始小鼠，然后繁殖以建立稳定的转基因品系。转基因小鼠脑和肝组织中特异性表达人MGMT转录本，体外MGMT活性测定结果显示转基因小鼠脑和肝组织中MGMT活性分别增加了150倍和250倍。Western blot分析证实转基因小鼠脑和肝组织中特异性合成人MGMT蛋白。
O6Methylguanine DNA methyltransferase (MGMT; EC 2.1.1.63) is an unusual DNA repair protein in that it directly and specifically repairs a premutagenic DNA lesion without involving other proteins. MGMT removes the alkyl group fromO6-alkylguanine in DNA in a unique stoichiometric reaction by accepting the alkyl group on a cysteine residue. The intracellular level of MGMT varies among tissues and appears to be inversely correlated to tissue-specific tumorigenesis induced by monofunctional alkylating agents. Because MGMT acts in solo, genetic manipulation of its expression may provide valuable insight into its contribution to cellular resistance to alkylation toxicity and to tumor induction. The human MGMT full length cDNA has been fused with a portion of the human transferrin (TF) 5'-flanking region (TF/MGMT). Transgenic founder mice were produced carrying the TF/MGMT transgene and then bred to establish stable transgenic lines. Human MGMT transcripts were specifically expressed in abundance in transgenic brain and liver tissues.In vitroMGMT assays revealed ∼ 150-fold and ∼25-fold increases in MGMT activity in transgenic brain and liver extracts respectively. Western blot analysis confirmed that human MGMT protein is specifically synthesized in transgenic brain and liver tissues.